Palladium fine particles are used as a catalyst (three-way catalyst) for purification of exhaust gas of automobiles (e.g., Patent Literature 1). However, when palladium fine particles are used as a catalyst, a problem arises in that their performance is significantly deteriorated due to poisoning by carbon monoxide etc. Rhodium fine particles are also used as a catalyst; however, they have the disadvantage of being expensive.
Catalysts using alloy fine particles have conventionally been proposed (Patent Literature 2 and 3). In addition, methods for producing Pd—Ru alloy fine particles have been proposed (Non Patent Literature 1 and 2).
Furthermore, Suzuki-Miyaura cross-coupling using Pd or the like as a catalyst has conventionally been practiced widely. In Suzuki-Miyaura cross-coupling reactions, it is important to inhibit a homocoupling reaction.